TRENTON — New Jersey residents may not get a chance to vote on a referendum this November asking if the state should dedicate up to $200 million a year to preserve open space.

Legislative leaders in the Senate and Assembly said today that so far, they haven’t been able to find enough lawmakers willing or able to return to Trenton during the summer to vote on the constitutional amendment with a looming Aug. 4 deadline to get it on the ballot.

And even if they could, it’s unclear the measure would actually have enough votes to pass.

E-mail messages between Assembly Speaker Sheila Oliver (D-Essex) and Assemblyman John McKeon (D-Morris), a prime sponsor, suggested there was a standoff with the Senate in which leaders of each house was waiting for the other to act first. Both later denied the assertion.

"As we discussed yesterday, Assembly leadership remains committed to open space funding, and has been working to make it happen — we have learned that the Senate does not intend to return to Trenton within the requisite timeframe, thus making any efforts on our part, moot," Oliver wrote today to McKeon in one of several e-mails obtained by The Star-Ledger.

But Senate President Stephen Sweeney (D-Gloucester) said he wants to hold a voting session, but can’t find enough lawmakers for a quorum. Only ten senators would be able to return on Monday and just 11 next Thursday, he said. The Senate needs 21 members present to hold a session, and 24 yes votes to get the measure on this year’s ballot.

"I just don’t have the members to come back. It’s not that we refuse to," Sweeney said this afternoon.

Sen. Bob Smith (D-Middlesex), another primary sponsor, has been working convince senators to come to Trenton for a vote, Sweeney said. McKeon noted that in a reply to Oliver, suggesting she and other leaders were unwilling to act.

"Senate leadership has told the environmental advocates that they are ready to return, but it is the Assembly’s lack of resolve that is keeping the matter from moving forward in a timely way," McKeon wrote. "One of the senators advised me that there is now a bipartisan effort to bring the Senate back for this purpose on Monday, July 29th, but only if the Assembly does the same."

Tom Hester, a spokesman for Assembly Democrats, said Oliver is also trying to find a day where enough members will be available to vote.

"The Assembly continues to research various alternatives to get something accomplished on open space — after, by the way, polling members several times as to their availability for a voting session before the deadline," Hester wrote in an e-mail this afternoon. "So, any implication that it’s not doing enough is false."

The resolution (SCR160) would ask voters to amend the state constitution to dedicate $200 million per year in sales tax revenue to preserve open space, farms and historic sites. The diversions would last for 30 years.

Both houses would need pass the resolution by a three-fifths majority — 48 out of 80 in the Assembly, 24 out of 40 in the Senate — to place the question on this year’s ballot.

An earlier and more costly version of the measure passed the Senate, 36-2, in June, but faced opposition in the Assembly after it was rushed to the floor on the last day before the summer recess.

The new resolution is a compromise, sponsors said. But Assembly Minority Leader Jon Bramnick (R-Union), a primary sponsor of the original open space measure, said even more changes may be needed.

"I don’t know if that’s the actual answer," he said of the new resolution, noting there had been "concerns on both sides of the aisle" over the original funding measure.

Bramnick said, however, that there was Republican support and he still believed a compromise would be reached.

"I know I’ve got a lot of members who are strong supporters," he said. "We’re going to come to some resolution."